Third-graders in a specific class were asked if they agreed with a new policy to have only one recess. The results are shown in the table. Calculate the marginal frequencies of the boys and the girls and find the difference. Boys who agree: 40
Boys who disagree: 32

Girls who agree: 44
Girls who disagree: 24

A. 0
B. 0.02
C. 0.49
D. 0.51

Afactory makes propeller drive shafts for ships. a quality assurance engineer at the factory needs to estimate the true mean length of the shafts. she randomly selects four drive shafts made at the factory, measures their lengths, and finds their sample mean to be 1000 mm. the lengths are known to follow a normal distribution whose standard deviation is 2 mm. calculate a 95% confidence interval for the true mean length of the shafts. input your answers for the margin of error, lower bound, and upper bound.